Sep 9, 2011

Greetings all. I’m sorry I couldn’t get this out sooner, but there was a slight power outage yesterday in my neck of the woods. In fact, it wasn’t slight at all. It was friggin’ huge and spanned from Mexico to Orange County, and from the coast to Arizona. Also, it was caused by one jack ass in Yuma.

Anyhoo, now that the power is back up thanks to the hard work of SDG&E workers, I am able to get this post out to you. Which is a handy one if you are a XenServer admin like myself.

So we have these few Windows XP VMs running in XenServer for our offshore developers to use. They used to be physical, but I P2V’d them so I could retire the old equipment they were on. After I got them up and running on XenServer the offshore guys started complaining about performance.

When I would log into those machines it was unbearable how slow it was, so I started investigating. It turns out that there is a known issue with Windows 2003 type VMs in XenServer and their virtual NICs. All you have to do to boost performance is simply disable Large Send Offload in the driver properties for the Citrix PV Ethernet Adapter. To do that follow these simple steps:

On the Advanced tab, click on Large Send Offload, and set the drop down to Disabled then click OK.

Now reboot the VM, and you should see a significant difference!

I am fairly new to the XenServer seen. So far I am really happy with it. I am a VMware VCP, so I have more experience in vSphere than I do in XenCenter. If you know of any other helpful XenServer tips, hook a brutha up in the comments!